Process of breaking emulsions



Patented Aug. 9, 1938 UNITED STATES PATENT OFFICE PROCESS OF BREAKINGEMULSIONS No Drawing. Application April 6, 1934, Serial No. 719,293

7 Claims.

This invention relates to a process for controlling the relative surfacetensions and interfacial adsorption between immiscible liquids to theend that emulsions of the liquids can be demulsifled when desired. Thisis a continuation in part of my application, Serial No. 567,753, filedOctober 8, 1931.

It has been observed for some time that in order for one liquid toemulsify in another liquid the liquids must be immiscible with eachother; they must have different surface tensions at the interface, andthe droplets must be prevented from coalescing. The coalescing may beprevented by a protective colloid, or by an adsorbed film of particleshaving dimensions larger than colloids, or by static electrical charges.Emulsions are broken by equalizing the surface tension at the interface,or by removing the protective colloid or neutralizing the electricalcharges.

By the present invention relative surface tensions or emulsificationtendencies of immiscible liquids are changed by the addition of suchsubstances that the surface tensions or emulsification tendencies ofliquids capable of forming emulsions are brought sufficiently near eachother to enable the emulsions to be broken when desired. The term"liquid is intended to include solutions of solids in liquids. The termemulsification tendency is intended to include the various surfacetensions and adsorption phenomena occurring at the interface.

Substances which can be used to control the surface tensions oremulsification tendencies of liquids to break emulsions when desired canbe obtained by oxidizing or blowing fatty substances such as animal orvegetable oils, (castor oil, for example), or by treating aldehyde-acidswith suitable chemicals. By blowing is meant heating the fatty substancewhile passing an oxygen containing gas through it. The particularsubstance to be used will depend upon the particular liquids to betreated.

By this invention the surface tension of one liquid can be changed withrespect to the surface tension of another liquid immiscible with it, ortheir relative emulsifying tendencies can be changed so that theemulsions break down. Breaking down of the emulsion may be due to theadsorption or dissolving of the protective colloid by the addedsubstance or the equalizing of the emulsifying tendencies by thesolution of the added substance in the continuous phase.

In carrying out this invention substances can be used for changing thesurface tensions or emulsification tendencies of liquids, whichsubstances are either so-called mixed compounds known as aldehyde-acids,or are substances from which aldehyde-acids can be obtained by chemicalreaction such as oxidation and/ or polymerization, or are substancesobtained by treating these aldehyde-acids with other compounds, or aremixtures of such substances. The aldehyde-acid compounds are at the sametime aldehydes and acids. The substances obtained from theaidehyde-acids for breaking the emulsions may be obtained from thealdehyde-acids by treating them with ammonia, or ammonia derivatives,such as alifatic and aromatic amides and amines, or sodium bisulphite,or hydrocyanic acid, etc., which will react with aldehydes or thecarbonyl group of the molecules, thus yielding amino compounds andaddition products of the reagents added, or by treating them withphosphorus chlorides, ozone, alcohols or alkalis other than ammonia andammonia derivatives, etc., which will react with the acid or carboxylgroup, thus yielding acylchlorides, or acid-peroxides, or esters, forexample. These mixed compounds may also be treated with halogens,whereupon the alde hydes form halogen derivatives. The solubilities ofthese substances vary greatly, so that some of them are water solubleand others are water insoluble and various ones of them differ as totheir solubilities in different immiscible liquids which form emulsions,such as oils and water, thus making it possible to vary the surfacetension of constituents of emulsions and control the adsorption at theinterface, thereby breaking the emulsions. By selecting the substancesto be added to the immiscible liquids the surface tension andemulsifying tendencies thereof can be so nearly equal ized thatemulsions of them can be broken down into the separate liquidscomprising the emulsion with very little loss of liquid.

A convenient way to prepare the substances that are to be utilized inregulating the surface tensions or emulsification tendencies ofimmiscible liquids is to oxidize carefully fatty substances such assemi-drying or drying or non-drying oils of animal or vegetable origin,preferably at a temperature of about 150 F. to about 350 F. with air orozone or ozonized air so that the aldehyde and peroxide content of theresulting oxidized oil will be as high as it is feasible to make it. Inthe claims where air is mentioned it is intended to include azone andozonized air. The oxidized products contain aldehyde-acids as well aspolymerized fatty acids and polymerized oxidation products of fattyacids. These oxidized products may be treated with one or more of thecompounds mentioned above which will react with them. Examples of oilsthat may be oxidized for this purpose are castor oil, rape-seed oil,corn oil, cotton-seed oil, linseed oil, soya bean oil, China-wood oiland fish oil, etc. Fatty acid esters of lower or higher alcohols thanglycerol, such as methyl, ethyl, propyl, butyl, or glycol esters, ormannitol or sorbitol esters, etc. may be used instead of the oils fromwhich to obtain the substances for controlling the surface tensions oremulsification tendencies of immiscible liquids, enabling emulsions tobe broken, as desired.

It has, also been found that these oils or other esters can be subjectedto destructive distillation and the products thereby obtained can beoxidized or oxidized and modified, as described above and utilized assubstances for breaking emulsions. Castor oil, for example, may bedestructively distilled for this purpose at a temperature of about 390F. to about 570 F. until a considerable portion of its weight has beenlost.

It has been found suitable in many instances to continue the destructivedistillation until about 1/5th of the weight of the oil is lost,although it is not necessary to carry the distillation to this extent.The time and temperature during the destructive distillation should beso regulated as to prevent a gel from being formed and also to preventglycerine from being split ofi. For the purpose of oxidizing the residueit is preferable to use a temperature of about 220 F. while passing airtherethrough.

When it is desired to break an emulsion, that substance is selectedwhich will equalize or substantially equalize the emulsifying tendencesof the two liquids, or that substance is added which will adsorb thecolloid present without itself being soluble in the continuous phase.

A simple test is usually sufficient in each instance to determine whatsubstance is to be used for de-emulsifying as soon as it is known whatliquids are present in emulsions already formed.

The following are given as specific examples illustrative of theinvention, but it is to be understood that they are by no meansexhaustive. It is also to be understood that the proportions given canbe widely varied and that the temperatures mentioned are those whichhave thus far been found to be the most suitable, but that they can bechanged.

Preparing a product for destroying emulsions The investigations whichhave been made up to this time indicate that the preferable way toproduce the product for breaking emulsions is as follows, but it is tobe understood that the invention is not restricted to this specific wayof producing the product for breaking emulsions.

Castor oil is rapidly heated to approximately 320 F. while air is beingblown through the oil at a rate of about fifteen cubic feet of air perminute per thousand pounds of oil until the darkening which isnoticeable at first begins to disappear. Ordinarily this will requireabout six hours. As soon as there has been a definite or decidedbleaching of the oil it is then rapidly cooled to the temperature atwhich the final blowing or oxidizing operation is to be carried out.During the cooling an iron salt of an organic acid, such as acetic,oleic, linolic and practically any other, may be added. For example,iron ricino-' leate is added as a catalyst to the oil in about one partper 200,000 by weight of the oil. This catalyst is added after thetemperature has become low enough to avoid the danger of the catalystbeing distilled over. It has been found that a temperature of about 285F. is most desirable for carrying out the oxidation after the catalysthas been added, when iron ricinoleate is usedas the catalyst, since, attemperatures much above this the iron ricinoleate distils out of the oiland at temperatures much below this its action is greatly weakened.Temperatures of about plus or minus 5 F. from 285 F. are about as widelimits as is practical with this catalyst. The time of treatment atapproximately 285 F. varies in accordance with the amount of air that isblown through the oil and the intimacy of the contact of the air withthe oil and also with the amount and nature of the catalyst present. Thenormal time required is usually about thirty hours.

Instead of using iron salts of organic acids, other metallic soaps, suchas manganese, tin. mercury, nickel, cobalt, or any other metal radicalwhich will show more than one valency, or which forms compounds withmore than one valency, may be used. The catalytic effect seems to bedependent upon the metallic portion of the compound or soap and the soapmay be produced directly from organic acids present in the castor oil bythe addition of metallic oxides, hydroxides, etc.

Breaking emulsions The following are given as specific examples ofbreaking emulsions, but it has been found that this invention isapplicable to the breaking of many other emulsions.

Example 1-.An emulsion of crude mineral oil and brine is vigorouslyagitated, preferably with gentle heating, to a temperature of about100-150 F. with about two-tenths of one percent by weight of castor oiloxidized as described above and the emulsion is allowed to stand,whereupon the emulsion separates into three layers after standing ashort time. The top layer contains practically all of the oil almostentirely free from water; the middle layer, which is quite thin comparedto the other layers, contains mineral oil, water and the addedsubstance; and the bottom layer contains practically all of the waterwith a very small amount of oil in it, usually less than 1% of oil. Theamount of the oxidized castor oil to be added depends somewhat upon thetype of the crude mineral oil emulsion that is to be broken.

When the protective colloid can be adsorbed by the oxidized oil theoxidized oil itself may be used without further treatment for breakingemulsions.

Example 2.-Anhydrous ammonia gas was bubbled through castor oil oxidizedas described above until it had become saturated.

One tenth to two-tenths of 1% of this saturated product was added to anemulsion of brine and oil, which was a typical petroleum oil fieldemulsion. The mixture was intimately mixed and slightly warmed and afterit was allowed to settle over night the emulsified water had completelyseparated into a clear lower layer, leaving free mineral oil in acondition fit for direct refining. The very small amount of reagentneeded was found in a thin layer between the water and oil layerconstituting less than A;% of the oil layer.

Example 3.An emulsion with water of castor oil oxidized as describedabove was formed by agitating in the presence of ammonia as anemulsifying agent. The concentration of this emulsion was about 10% ofoxidized oil. This prepared emulsion was then intimately mixed with atypical petroleum oil field emulsion and warmed to about 100 to 150 F.After being allowed to settle over night the petroleum oil-wateremulsion had settled, leaving the petroleum oil in perfect condition forfurther refining.

Example 4.Anhydrous S02 gas was bubbled through castor oil oxidized asdescribed above until it had become saturated. The procedure describedin Example 2 was followed and similar results were obtained.

Emmple 5.-The procedure described in Example 2 was followed except thatthe ammonia saturated oil was first dissolved in benzol and the solutionused instead of the saturated product with results like those describedin Example 2.

I claim: 7 r 7 1. The process of breaking emulsions, which comprisesmixing with emulsified liquids castor oil that has been bleached byoxidation at a temperature of about 320 F. and then oxidized by blowingair through it while the oil is at a temperature of approximately 285 F.

2. The process of breaking emulsions, which comprises mixing withemulsified liquids castor oil that has been bleached by oxidation at atemperature of about 320 F. and then oxidized by blowing air through itwhile the oil is at a temperature of approximately 285 F. for about 30hours, said oxidized oil being unsaponifled.

3. The process of breaking emulsions, which comprises mixing withemulsified liquids castor oil that has been bleached by oxidation at atemperature of about 320 F. and then oxidized by blowing air through itwhile the oil is at a tem- 4. The process of breaking emulsions, whichcomprises mixing with emulsified liquids castor oil that has beenbleached by oxidation at a temperature of about 320 F. and then oxidizedby blowing air through it while the oil is at a temperature ofapproximately 285 F. in the presence of an organic salt of a polyvalentmetal, said oxidized oil being unsaponified.

5. The process of breaking emulsions, which comprises mixing withemulsified liquids castor oil that has been bleached by oxidation at atem-- perature of about 320 F. and then oxidized by blowing air throughit while the oil is at a temperature of approximately 285 F. in thepresence of an organic salt of iron, said oxidized oil beingunsaponified.

6. The process of breaking emulsions, which comprises mixing withemulsified liquids castor oil that has been bleached by oxidation at atemperature of about 320 F. and then oxidized by blowing air through itwhile the oil is at a temperature of approximately-285 F. until itcontains an appreciable amount of aldehyde-acids and peroxides, saidoxidized oil being unsaponifled.

'7. The process of breaking emulsions, which comprises mixing withemulsified liquids castor oil that has been bleached by oxidation at atemperature of about 320 F, and then oxidized by blowing air through itwhile the oil is at a temperature of approximately 285 F. and modifiedby chemical reaction to render it soluble in one of said liquids, saidoxidized oil being unsaponifled.

IVOR MILTON COLBETH.

CERTIFICATE OF CORRECTION Patent No. 2,126,568.

ug s 9. a.

IVOR MILTON COLBETH It is hereby certified that error appears in theprinted specification of the above numbered patent requiring correctionas follows: Page 1, second column, line 51, for "azone" read ozone; page'5, first column, line 25, after "285F," insert the comma, words andperiod said oxidized oil being unsaponified.; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the ease in the Patent Office Signed and sealedthis 15th day of September, A. D, 1938.

(Seal) Henry Van Arsdale Acting Commissioner of Patents.

